<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        body{margin: 0;padding: 0}
        .wrap{
            margin: 10px;
            background-color: aqua;
        }
        p{
            margin: 20px;
            background-color:blanchedalmond;
        }
    </style>
</head>
<body>
    
    <div class="wrap">
        <p>this is a paragraph, and has a 20px margin.</p>
    </div>
</body>
</html>